1. Field of the Invention
The present disclosure generally relates to assemblies for and methods of accelerating cooling in thermally activated active material actuators, and more particularly, to assemblies for and methods of accelerating cooling within such actuators utilizing both permanently and selectively engaged heat sinks.
2. Discussion of Prior Art
Thermally activated active material actuators, such as shape memory alloy (SMA) wires in the Martensite state, are activated by heating the material above an activation temperature. With respect to SMA wires, this generally causes the material to undergo phase transformation to Austenite, and contract in a manner that can be used to do work. Once activated, the actuator must undergo a relatively lengthy cooling period, wherein the temperature is lowered to a point below its transformation temperature, prior to being re-activated. During this period, the actuator is unavailable to do work, such that the duration of the cooling period substantially contributes to the total bandwidth of the actuator. Thus, it follows that reducing the predominate cooling period significantly increases the bandwidth.
Conventional methods of cooling, however, including simply exposing the material to ambient conditions, are often insufficient to meet these goals, and/or involve complex peripheral systems, such as forced air convection, etc. These concerns especially arise in the performance of active material actuators that are required to undergo rapid successive activations and/or effect quick return (e.g., <1 s) actuation. As such, there remains a long felt need in the art for an efficient assembly for and method of improving bandwidth by reducing the cooling period.